Current methods of melting pelletized thermoplastic adhesive materials utilize a tank that is resistance heated to melt by heat conduction from the walls of the tank. Thermoplastic materials are poor thermal conductors. Extensive time is required to melt the entire body of material and additional electrical power is required to maintain the material in a liquid state. If tank wall surface temperatures are allowed to exceed the material application temperature to expedite melting, material degradation will occur. Many materials held at application temperature for an extended period will degrade in performance and foul the application apparatus.
Large tanks of colored polymer are propane fired or melted by heat exchange from heated oil and stirred to maintain a large batch of road striping material for intermittent application. Large tanks of asphalt are fired by propane, or resistance element heated to melt for roofing operations. Both of these applications experience overheating and start up delay, and are energy inefficient.